Injection-locked oscillators (ILO) are oscillators that exhibit the characteristic that the oscillation frequency can be locked to a frequency of an external injection signal rather than to its inherent resonance frequency, or free-running frequency. ILOs are usually based on cross-coupled transistors and tank circuits, and have been employed for frequency division.
Recently, polar receiver architectures using ILOs have been proposed that extract the modulation envelope and phase components from a received non-constant envelope modulation signal without using a carrier recovery circuitry. However, the proposed polar receiver architectures and associated signal processing have limitations or deficiencies that result in poor performance and high bit error rates (BER). Accordingly, there is a need for improved ILO configurations in polar receiver signal processing and architectures, as well as for other uses.
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